Preparation And Properties Of Polypropylene Based Building Formwork

Wood-plastic composites(WPC)is a new type of composite material which has been booming in recent years at home and abroad.It refers to the use of polyethylene,polypropylene and polyvinyl chloride to replace the usual resin adhesives,wood flour,rice husks,etc Straw and other waste plant fiber mixed into new wood materials,and then after extrusion,molding,injection molding and other plastic processing technology,produced plates or profiles.Mainly used in building materials,furniture,logistics packaging and other industries.Good processing performance.In this paper,polypropylene(PP)as matrix,elastomer as TPU,rice husk powder and wood powder as fillers were prepared by hot pressing method.The mechanical properties and processing properties of the materials were tested.The main results are as follows:(1)Polypropylene(PP)as matrix wood-plastic composite was prepared by melt blending method.The toughening effect was improved by adding thermoplastic polyurethane elastomer(TPU).Firstly,rice husk powder was used as filler.The compatibility of rice husk powder and PP was improved by pretreatment of rice husk powder.The compatibility of rice husk powder and PP was mainly improved by adding coupling agent.The addition of nanometer calcium carbonate could increase the impact strength and change the content of different rice husk powder.Effects of different particle size and TPU content on mechanical properties,processability and heat resistance of wood-plastic composites.The results showed that the content of rice husk powder was 6.7,and the content of thermoplastic polyurethane was in the base.The tensile properties,elongation at break and impact properties of the composites were the best when the volume content was 3%,and the processing property was better with the increase of TPU content.The mechanical properties of the composites increased first and then decreased.The tensile properties of the composites decreased with the increase of rice husk powder content,and the impact properties increased first and then decreased.When the particle size of rice husk powder was 100 mesh,The tensile properties were better than those of wood-plastic composites made of rice husk powder of 60 mesh and 80 mesh.The best ratio was PP and TPU with 6.7%mesh rice husk powder content of 6.7%mesh and 93.3%matrix,in which TPU had better comprehensive properties when the ratio of TPU to thermoplastic polymer was 3.(2)With wood flour as filler,the experimental results showed that the tensile properties,elongation at break and impact properties of the composites with wood flour content of 6.7 and thermoplastic polyurethane content of 5%were the best,and with the increase of TPU content,the tensile properties,breaking elongation and impact properties of the composites were the best.The mechanical properties of the composites increased first and then decreased,and the tensile properties of the composites decreased with the increase of rice husk powder content.The best ratio is PP and TPU with 6.7%mesh rice husk powder content of 6.7%matrix and 93.3%matrix.The mechanical properties of PP and TPU are the best when TPU occupies 5%of thermoplastic polymer.(3)The effects of two flame retardants,magnesium hydroxide and aluminum hydroxide,on the flame retardancy of polypropylene based wood-plastic composites were studied.When 5%aluminum hydroxide or 10%magnesium hydroxide was added,The flame retardant grade of the composite is up to the third grade of the Japanese JISD 1201-77 standard,which meets the requirements of the building formwork.(4)Considering the mechanical properties,flame retardancy and other aspects,the optimum ratio of polypropylene based wood-plastic composites is as follows:5%aluminum hydroxide 6.33%pretreated rice husk powder 86%...